The United States and NATO are poised to launch a major assault in the Marjah district in southern Afghanistan. Tens of thousands of Afghan civilians are in imminent peril. Will President Obama and Congress act to protect civilians in Marjah, in compliance with the obligations of the United States under the laws of war?

Few civilians have managed to escape the Afghan town of Marjah ahead of a planned US/NATO assault, raising the risk of civilian casualties, McClatchy News reports.

Under the laws of war, the US and NATO -- who have told civilians not to flee -- bear an extra responsibility to control their fire and avoid tactics that endanger civilians, Human Rights Watch notes. "I suspect that they believe they have the ability to generally distinguish between combatants and civilians," said Brad Adams of Human Rights Watch. "I would call that into question, given their long history of mistakes, particularly when using air power. Whatever they do, they have an obligation to protect civilians and make adequate provision to alleviate any crisis that arises," he said. "It is very much their responsibility."

"If [NATO forces] don't avoid large scale civilian casualties, given the rhetoric about protecting the population, then no matter how many Taliban are routed, the Marjah mission should be considered a failure," said an analyst with the International Crisis Group.

A report in the Wall Street Journal cast fresh doubt on the ability -- and even on the interest -- of U.S. forces to distinguish combatants from civilians. "Across southern Afghanistan, including the Marjah district where coalition forces are massing for a large offensive, the line between peaceful villager and enemy fighter is often blurred," the Journal says. The commander of the U.S. unit responsible for Pashmul estimates that about 95% of the locals are Taliban or aid the militants. Among front-line troops, "frustration is boiling over" over more restrictive rules of engagement than in Iraq, the Journal says -- a dangerous harbinger of potential war crimes when the U.S. is about to engage in a major assault in an area densely populated with civilians.

Today, AFP reports, military helicopters dropped leaflets over Marjah as radio broadcasts "warned residents not to shelter Taliban ahead of a massive assault." Doesn't this suggest that the invading U.S. forces may regard any civilian alleged to be "sheltering Taliban" as a legitimate target, including women and children?

If the U.S. assault in Marjah results in large scale civilian casualties, the U.S. will have committed a major war crime. If the United States cannot protect civilians in Marjah, as the U.S. is required to do under the laws of war, the assault should be called off. Under international law, every U.S. citizen is legally obligated to work to bring about the compliance of the United States with international law. Raise your voice now, before it is too late.